COREC: MODELING Core C, "Modeling" will integrate all data generated by the four Projects within the framework of a consistent mathematical description of middle ear pressure-regulation in health and disease. The overall goal of Core C is to provide support services to Core B and to each of the four Projects regarding interpretation of the test data in terms of their functional relevance. A secondary goal is to complete the mathematical description of middle ear pressure-regulation for later interrogation with respect to the validity of proposed pathogenic mechanisms and the expected efficacy of current and future otitis media treatments. The specific aims are to: 1) develop a complete descriptions of ME pressure-regulation;2) apply our previously developed biomechanical model of Eustachian tube function to the test results of children and adults enrolled in Projects 1 through 4 and abstract and quantify those properties that are relevant to testing each Project's hypotheses;3) apply our biomechanical model to Eustachian tube function test data available from pressure-chamber studies and identify those mechanical properties that can be extracted from these test protocols;4) calibrate our previously developed 3-D functional-anatomical model of the ET system using the available vector and mechanical data for Projects 2 and 3 and determine the anatomical constraints imposed on the efficiency of Eustachian tube function, and 5) calibrate the 3-D functional-anatomical model using the MRI and Eustachian tube function data from Projects 1, 2 and 3 and describe the mechanics of ET opening in adults and in children with and without cleft palate and with and without otitis media. The anticipated effort distribution of Core C is 10% Core B, 30% Project 1, 25% Project 2, 25% Project 3 and 10% Project 4.